Pattern chains



Nov. 21, 1961 1.. s. URQUHART ETAL PATTERN CHAINS E u n M. H fr "in" m L L y V a v mm nw n @fiwww ,3 MU MMW fl M mm My m, M N W I r x I Filed Aug. 2, 1956 um H hm M mm W United States Patent 3,009,488 PATTERN CHAINS Lloyd G. Urquhart, Westboro, and Bernard Thal, Boston,

Mass, assignors to H. F. Livermore Corporation, Suffolk County, Mass., a corporation of Delaware Filed Aug. 2, 1956, Ser. No. 601,772 3 Claims. (Cl. 139-333) This invention relates to the pattern chains which are used in the head motions of cloth looms to govern the action of the head motion which in turn actuates the harnesses and controls the shuttle box motion to produce the desired pattern or weave of fabric.

These pattern chains are in many instances exceedingly heavy; a 140-bar warp chain as constructed hitherto wholly of metal will weigh 500 lbs. or more, being 15 or more feet in length, up to half of which weight must be lifted and supported by the buckets on the shaft of the head motion, by engagement with the risers on the steel bars of the pattern chain. The links which unite the bars to form the chain have for lightness been conventionally made of sheet metal, with a simple eye or hole in each end fitting over the end of a chain bar, the adjacent ends of succeeding links overlapping each other and retained in place on their common bar by a cotter pin put through the end of the bar outside them.

Because of the scant bearing area in each eye, no wider than the thickness of the stock from which the link is punched, both the eyes and the bars soon wear out of round at their points of mutual engagement, since the use of applied lubricant is seldom resorted to because of the danger of its escape onto the warps and filling and the fabric being worn, with costly damage to the quality of the latter.

When such wear of the eyes and the ends of the bars occurs, the spacing apart of the bars increases and the risers carried thereby do not properly enter the buckets on the head motion shaft, but stand upon the divisions or fins which define the buckets as the risers enter the space beneath the shoes on the vibrator levers. These levers carry the vibrator gears which are brought into mesh with the upper and lower cylinder gears periodically in accordance with the pattern, the gears operating the jacks through connectors and thus shifting the harnesses and the shuttle boxes to effect the desired weave.

The vibrator levers have little scope of movement beyond that required for the risers to pass under and lift them when the risers are properly seated in the buckets. But when slack develops in the eyes of the links and the risers ride up on the divisions or fins where there is not room for them to remain as they are drawn under the shoes of the vibrator levers, the engagement with the shoes forces the set of risers and their chain bar to snap down into the bucket and jerk the chain. This reacts on the other parts of the head motion, through the inertia of the heavy chain, causing the vibrator levers to move out of time, even delaying the engagement of the vibrator gear with the cylinder gear until one or more teeth of the latter have passed. As a result, the harness is not moved correctly, causing a wrong weave in the pattern of the fabric, or, worse, stripping a tooth on the cylinder gear or breaking a jack, vibrator lever, or connector, in any event resulting in serious delay and loss of production of the loom. In brief, jerky pattern chain movemnt throws out the loom timing, usually with well known and costly damage.

.Additionally, the excessive weight of prior all metal pattern chains has forced the long ones to be regularly dragged along the floor in moving them to and from the loom and in setting them up. This rough handling frequently knocks a cotter pin out of its hole in the end "ice of a chain bar, with resulting detachment of the links and escape of the risers and sinkers from the bar. Such disarrangement of the pattern and the recapture and replacement of the risers and sinkers, with reference back to the chain draft and rechecking to verify the pattern, is also a familiar nuisance. The very weight of the chain calls for more than one pair of hands to handle it, and limits the work to employees of more than average strength.

To overcome these drawbacks, the invention provides a novel pattern chain in which wear at all points is eliminated or rendered negligible and insignificant in amount, without using lubrication, and the weight is reduced to about 5 of that of the all-metal prior type. These results are attained by the use of risers, sinkers and links of novel form made from synthetic plastic materials characterized by a coeflicient of friction so low as to be practically immune to wear in the absence of all applied lubricant. The preferred material for this purpose is nylon, though Teflon and other plastics having the required characteristics are contemplated for use.

The invention takes further advantage of the characteristic of inherent lightness of the component plastic in order to make a practicable and enduring pattern chain. The specific gravity (weight) of nylon being about /7 that of steel, and the load on the bearing surface of the component parts being solely the weight of the chain, this bearing load is far below that at which any heating can occur through relative motion thereat at the slow speed of travel of the pattern chain, and in the absence of heating the wear life of nylon bearing surfaces is practically unlimited.

A novel form of riser is provided, adapted to maintain full tread width and diameter and hence accurate actuation of the vibrator levers throughout prolonged use, and the improved construction and cooperation of the new sinkers with the risers insures the maintenance of precise positioning of the risers and avoidance of lifting the wrong vibrator levers, throughout an enduring period of use, by substantially complete elimination of end wear with resulting end-play.

A novel form of chain link is provided whereby the pivotal connection between adjacent links is removed from the chain bar and transferred to the links themselves. The chain bars are mounted within a hub on each link which serves as the pivot on which the adjacent link swings, and hence the bars are simply carried by the links with no rotation in the links and thus no wear of the co-engaging surfaces of rods and links caused by flexing of the chain. Since the coefficient of friction of nylon on dry nylon, as here at the pivots of the links, is less than half that of nylon against steel even when the latter is oil-lubricated, wear at the pivots is practically nil. Also, the length of the bearing surface in contact with the chain bar is increased to about four times that of the conventional steel link, by virtue of the hub method of joining the links, impartinggreat resistance to flexing of the chain in the unwanted edgewise direction under the vibration of the running loom; each link is held strictly in right-angle relation to its bar. Thus the chain runs smoothly throughout its life without any jerking or faltering to upset the timing of the head motion action.

While the use of steel chain bars is retained in the case of long and wide pattern chains it is contemplated to use plastic rod stock to make these chain bars where special circumstances warrant the expense and the width and length of the chain permits asin the case of the box motion chain.

Other aims of the invention, and the manner of their attainment are as set forth hereinafter.

An illustrative embodiment of the invention is shown in the accompanying drawings, in which FIG. 1 is a perspective view of harness and box motion pattern chains of the new construction, together with the head motion shaft and buckets which drive the chain.

FIG. 2 is a plan view of one of the novel links forming the chain.

FIG. 3 is a longitudinal section through two adjacent links of the chain of FIG. 1.

FIG. 4 is a diametnic section of one of the risers.

FIGS. 5 and 6 are alternative forms of links embodying the invention.

The novel pattern chain comprises two parallel runs of side links 1 formed of nylon, each having a broad partcircular end portion and a narrower waist portion between. One end portion 3 of each link is fiat and has a concentric aperture 5 forming an eye that is flat in the sense that it does not extend laterally of the link beyond the thickness of end portion 3, while the other end 7, of equal thickness to the end 3, is offset from the plane of the end 3 by a distance equalling the thickness of end 3 and provided with a laterally extending fixed sleeve, preferably in the form of an integral concentric hub 9, slightly longer than the thickness of end 3, and accurately fitting within the hole 5 of an adjacent identical link. As shown in FIG. 3, the successive links are overlapped and assembled in interlocking relation with the holes or eyes 5 of each in place on the hubs 9 of the respective preceding links. With the exception of the means to hold the eyes on the hubs, the chain is thus complete independently of the chain bars which heretofore have been relied on to hold the links together in chain form.

Each hub 9 has an internal bore or passage 11 accurately fitting the end portion 13 of the chain bar on which it is mounted. Instead of a mere cotter pin hole, both ends of each chain bar 15 are formed with a rabbet 17 all the way around and as close to the slightly rounded end of the bar as is practicable. As fast as assembled, a metal retaining clip 16 is snapped into place Within the rabbet 17. Thus each link 1 pivots n the hub 9 of its preceding link, while its own hub forms the pivot for the succeeding link, and so on throughout the chain. As the chain bar 13 is carried wholly within the passage 11 of the link mounted thereon, and no relative rotation of the bar within such passage occurs as an incident of flexing the chain, the fit of bar 13 in the passage of hub 9 can be tight if desired, or loose as preferred for ease of assembly. The same manner of construction and relation is adopted Whether the chain bar be of metal or of plastic.

For strength, the mid-length or waist 19 of each link is made equal in thickness to twice the thickness of each end portion 3, 7, and such thickened structure terminates in a curve 21 concentric with the axis respectively of the hole and passage 11. Thus, though the two ends of each link are ofiset, when assembled the chain has equal continuous parallel side faces.

The width of the ends 3, 7, is greater than the radial extent of the clips prongs or tail, so there is no chance of knocking oi the clips in dragging the chain along the floor.

The use of synthetic plastic material and a molding technique in making links enables them to be made in the form shown cheaply and easily, as against the attempt to attain the advantages of the novel shape in metal, which could be prohibitively expensive. The improved form is adapted to be molded in multiple or gated form by injection molding processes rapidly and at low cost, especially as the units come from the mold in finished form requiring no further processing.

The novel riser 25 of FIGS. 1 and 4 is likewise made of nylon or other suitable synthetic plastic material in circular form by multiple injection molding. It is characterized by a tread 27 of approximately the width of the shoe on the vibrator lever and which is of true cylindrical shape having a profile flat in axial extent throughout the entire width of its tread, with sharp rectangular peripheral edges. This is in distinction to the conventional pressed metal riser, in which through the nature of the forming operation required the tread have rounded edges which limit the useful width of its tread to less than its full axial extent. Its hub 29 is slightly' longer axially than the Width of the tread, so that there is no contact between the rims of adjacent risers when set hub to hub as frequently required by the pattern. The bore 31 of the hub is a loose fit on the chain bar 13 to permit free rotation of the riser thereon; when made of nylon, it turns with negligible friction or wear. The web 33 joining the hub and rim is molded with a cross-section each lateral side of which is defined by a curve approximating the arc of a circle having a radius r, thus giving full support to the side margins of the tread 27 with the use of a minimum amount of stock, and also decreasing the weight of the riser even beyond the saving in this respect derived from the use of plastic instead of metal.

The novel sinkers or spacers 35, 37, are also molded from nylon or other suitable synthetic plastic material. They have an internal bore fitting easily and slidably upon the chain bars 13 and an external diameter small enough to pass under the vibrator lever shoes Without engagement therewith. The Wall thickness is only such as is needed to stand handling and to provide adequate bearing against the hubs of the risers. They are made both in lengths equalling the spacing of the vibrator levers in the head motion, as shown at 35, and also in multiple of such length as shown at 37. When made of nylon, they are practically immune to wear, and hence no endplay develops.

Since the wear of the links at their pivoting points or interconnections is insignificant and practically nil because relative movement is confined to surfaces of nylon upon nylon, and the length and pitch of the chain never change through use, the sets of risers 25 on each chain bar are always presented accurately to the buckets defined by the usual steel fins 39 staked in slots cut therefor in the head motion shaft 41 with their ends held in slots in the sprockets 43 fixed on the shaft. The result is that the novel chain runs easily and smoothly and exerts precise and accurately timed control of the head motion and the motions controlled thereby, throughout a period of greatly prolonged life. It is much more easily handled, and is less subject to deragement through rough handling. The low-friction characteristic of the nylon treads of the risers lets them slide under the shoes on the vibrator levers, as they must do to lift the latter, much more easily than with metal risers, thus reducing wear and the power needed to drive the head motion, in addition to the power saved by the lessened weight of the whole chain.

While we have illustrated and described certain forms in which the invention may be embodied, we are aware that many modifications may be made therein by any person skilled in the art, without departing from the scope of the invention as expressed in the claims. There fore, we do not wish to be limited to the particular forms shown, or to the details of construction thereof, but

What we do claim is:

1. A pattern chain having in combination links each having a nylon hub at one end and a flat nylon eye at the other end for the reception of the hub of a similar adjacent link, bars each extending through the hubs of two links standing opposite each other at opposite sides of the chain, means retaining the links on the bars, and risers on the bars.

2. A pattern chain having in combination synthetic plastic links each having a hub on which the succeeding link is pivoted and an eye fitting over the hub of the preceding link, chain bars each extending through the hub of a link and the eye of an adjacent link at each side of the chain, risers and sinkers of synthetic plastic material on the bars, and forked retaining means on at least one end of the bars holding the links on the bars, the latter being grooved for the reception of such means.

3. A side chain link for pattern chains having both end-portions of substantially the same thickness and each offset from the plane of the other by the amount of such thickness, the mid-length portion of each link having twice the thickness of each end-portion.

References Cited in the file of this patent UNITED STATES PATENTS Mead Apr. 9, 1918 Livermore Mar. 31, 1925 Harris Aug. 12, 1941 Shortland Nov. 15, 1949 FOREIGN PATENTS Great Britain of 1891 Great Britain June 6, 1956 Germany Apr. 19, 1956 

